Reinforce your doorframes and window frames, preferably with steel. The dinky pine wood frames of residential doors and windows are hilariously easy to kick in, and the thickest steel door and the meanest window bars in the world won't mean much when an attacker can simply kick them out of the frame with a minimum of effort.

You will probably find that doing this is in fact deemed illegal by at least one entity in your local hierarchy of state/county/municipality. I'll give everyone three guesses as to why.